Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:99669
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.223.174 as permitted sender)
MIME-Version: 1.0
Sender: kalle.php@gmail.com
In-Reply-To: <CAEsg9X1cxQY+TBM2Q0zsdvc0QcfrJMxgfefNtdoFstWxfrrJYg@mail.gmail.com>
References: <CAEsg9X0sJ=JYxHfAs6a2Pp4Oymtkqi+JcDfX2+u4MP_pZTK9NA@mail.gmail.com>
 <CAJW__o3ynh3C=CBxD4LaLyE9DsLPhBExyvCgtabvn4cYuz4Vxg@mail.gmail.com>
 <CAEsg9X3EbgYiMdA8eUV1usKBTfJSbiJFG7E7mU4-hBRaAP+uyg@mail.gmail.com> <CAEsg9X1cxQY+TBM2Q0zsdvc0QcfrJMxgfefNtdoFstWxfrrJYg@mail.gmail.com>
Date: Thu, 29 Jun 2017 04:57:12 +0200
Message-ID: <CAJW__o3PtvPzQo+yk=3sm8mE-ytZUJ-Cbo8iXgK4zs3Uyhb_KA@mail.gmail.com>
To: David Rodrigues <david.proweb@gmail.com>
Cc: PHP Internals <internals@lists.php.net>
Content-Type: text/plain; charset="UTF-8"
Subject: Re: [PHP-DEV] Final variables
From: kalle@php.net (Kalle Sommer Nielsen)

2017-06-29 1:07 GMT+02:00 David Rodrigues <david.proweb@gmail.com>:
>   readonly $number = mt_rand();
> I agree that "readonly" is a better keyword, but we have to points here:
> 1. "final" is used on some language (Java, C++ I guess);
> 2. "final" keyword does exists on PHP with a "similar" behaviour;

> If we can implements "readonly" is good too, because turn it more implicit.
True we could re-use the final keyword, but think about it this way,
we got final methods and final classes which means it cannot be
overridden/extended respectively, if the final keyword then would also
apply to variables but it would mean they could not be written to,
that would create a WTF-factor.

The readonly keyword would work for any visibility modifiers, so
inherited classes or extending classes may read a protected property,
but not modify it as well:

class A {
 protected readonly $b;

 public function __construct() {
  $this->b = 'C';
 }
}

class B extends A {
 public function read() {
  echo $this->b;
 }

 public function write() {
  $this->b = 'D';
 }
}

$b = new B;

$b->read(); // "C"
$b->write(); // <- error


-- 
regards,

Kalle Sommer Nielsen
kalle@php.net